set1={1,2,1,3,4,5}
print(set1)

list=[1,2,1,3]
set2=set(list)
print(set2)
set2.pop()
print(set2)
my_dict1={"lijie":99,"xx":33}
my_dict1={"lijie":33}
#修改后的直接作用于原字典
print(my_dict1["lijie"])
print(my_dict1.pop("lijie"))
#直接移除，移除后可以打印
mydict={"lijie":22,"chencu":33,"kang":44}
keys=mydict.keys()
for x in keys:
    print(x)
    print(mydict[x])